(Continued from p. 1 ) 



in the wet sand at the water's edge. And if he has 

 strolled the beach at night, he has probably 

 watched ghost crabs scamper across the sand in 

 their nightly feeding rituals. 



For the beach lover, these creatures of the sea 

 and sand are an integral part of the coastal magic. 

 To the naturalist, they mean something more. 

 They are environmental barometers — indicating 

 just how man and his development are affecting 

 the delicate balance of nature in the coastal region. 



Birds are among the best environmental 

 barometers. Because they are easily affected by 

 any kind of contaminants, they quickly reflect en- 

 vironmental problems. And they are relatively easy 

 to observe. 



"Birds are probably the most visible animals 

 we have. If changes are occurring in a bird popu- 

 lation, even an amateur ornithologist might notice 

 it." That's the contention of Dr. Robert Soots, an 

 ecologist with Campbell College. 



Taking the census 



Along with Dr. James Parnell of UNC at Wil- 

 mington, Soots has spent the past four summers 

 carefully noticing North Carolina's coastal birds. 

 Until they began to take a census of the state's 

 coastal birds last summer, population figures had 

 been little more than educated guesses. When Par- 

 nell and Soots finish their Sea Grant-supported 

 work this summer, they will have established a 

 count which can serve as a baseline for future 

 reference. 



Late this month, many species of colonial birds 

 (those that nest in groups) will begin nesting. In 

 May, Parnell and Soots and eight or 10 graduate 

 students will take to the field and begin the labori- 

 ous task of counting. They will use aerial photog- 

 raphy to count some species, such as Royal Terns 

 and Black Skimmers. For other species, the task 

 calls for crawling through brush and climbing 

 trees. 



In the smaller colonies, of no more than 2000 

 birds, the census is taken by actually counting 

 each nest. Because the birds nest in pairs, the re- 

 searchers double the number of nests to get the 



total number of adults in the colony. A counting 

 crew visits each colony twice between the period 

 of maximum laying and hatching for that particu- 

 lar species. Birds that habitually nest together — 

 such as the Sandwich Tern and the Royal Tern — 

 cause added difficulties for the census takers. Their 

 laying seasons may be radically different. 



In larger colonies, Parnell and Soots may use 

 the strip census. All the nests within a certain 

 diameter strip are counted. Soots adapted another 

 technique used widely by foresters to measure 

 volumes of timber. Called the point center tech- 

 nique, it seems to work if the nests in a colony are 

 randomly scattered throughout the site. 



'Heronries are a fit' 



But it is not always easy going. They have found 

 no suitable method for estimating the heron popu- 

 lation. "The heronries are a fit," said Parnell. 

 "They are absolute chaos. You might have nine 

 different species in two dimensions. You have to 

 climb trees and crawl on your hands and knees." 



To make matters worse, young herons will re- 

 gergitate on anyone who disturbs them. And there 

 are two or three types of herons sometimes nesting 

 together whose eggs are too similar to distinguish 

 under field conditions. The counting process is 

 compounded by the problem that if the adult birds 

 are frightened away from their nests for long 

 periods of time, the eggs may become overheated 

 from exposure to the sun. So the counting in 

 colonies where adult birds are likely to leave their 

 nests must be done within an hour. That group 

 includes most of the birds who nest on the ground. 



Last summer Parnell and Soots counted 11 

 species of long-legged waders — the herons, egrets 

 and ibises. The most common bird in this group 

 was the White Ibis, which had about 3000 nests. 

 The Louisiana Heron and the Cattle Egret weren't 

 far behind, with about 2700 and 2400 nests respec- 

 tively. About 90 percent of the total of 27,000 birds 

 in this category nested in man-modified sites, 

 mainly on dredge islands. 



(See "Census-taking," p. 6) 



v ^ t m 



